Nuclear testing at Bikini Atoll consisted of the detonation of 24 nuclear
weapons by the United States between 1946 and 1958 on Bikini Atoll in the
Marshall Islands. Tests occurred at 7 test sites on the reef itself, on the
sea, in the air, and underwater. The test weapons produced a combined yield of
42.2 Mt of TNT in explosive power.
The United States and its allies were engaged in a Cold War nuclear arms race
with the Soviet Union to build more advanced bombs from 1947 until 1991. The
first series of tests over Bikini Atoll in July 1946 was codenamed Operation
Crossroads. The first bomb, named Able , was dropped from an aircraft and
detonated 520 ft (160 m) above the target fleet. The second, Baker , was
suspended under a barge.